4. Heart Sound and Blood Pressure

Question 1

Heart sound signals

Answer 1

phonocardiogram signals (PCG)
result of contraction and relaxation of atria / ventricles / valves / blood flow

Question 2

Parts of heart sound

Answer 2

1. ventrical contraction, 50-100 ms, 30-100 Hz
2. ventrical relaxation, 25-50 ms, >100 Hz
3. sudden end of rapid-filling phase of ventricles
4. atria contract

Question 3

Microphone for PCG

Answer 3

two types - crystal and dynamic

1) crystal - contains piezoelectric material, generates V when sound waves occur
2) dynamic - contains coil and magnetic core, generates V when heart sounds cause mvmt in coil

Question 4

Heart Murmer

Answer 4

• extra sound produced by heart, from turbulent blood flow in vessels
• caused by reduced blood viscosity, reduced diameter
• four levels

Question 5

Stenosis vs Regurgitation murmer

Answer 5

S: Valve cannot be completely opened, blood flows through small opening
R: valve cannot be completely closed, blood back flows

Question 6

Blood Pressure

Answer 6

indication of circulation of blood in the body
two components: systolic, diastolic
- low: severe bleeding, heart failure
- high: narrowing of arteries

Question 7

Blood Pressure Measurement techniques

Answer 7

1. non invasive
   - first pulse you hear = SP, last pulse you hear = DP
   - cons: noise effects, excessive msmts
2. invasive
   - insert catheter into blood stream